Trailer signal converter

ABSTRACT

A trailer signal converter includes a plurality of inputs, including a first towing vehicle turn light signal, a second towing vehicle turn light signal, and a trailer brake signal. The trailer brake signal is a pulse-width modulated signal. The trailer signal converter selectively drives the turn and stop light signals on the trailer based on the input signals. In a three-wire system, the signal converter is configured to receive a brake signal input and a brake light input and selectively drive the trailer stop light signals.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/840,812, entitled “TRAILER SIGNAL CONVERTER,” filed on Aug. 31, 2015,now U.S. Pat. No. 9,428,105, which is a continuation of U.S. patentapplication Ser. No. 14/195,424, entitled “TRAILER SIGNAL CONVERTER,”filed on Mar. 3, 2014, now U.S. Pat. No. 9,120,424, which claimspriority to U.S. Provisional Patent Application No. 61/771,616 entitled“TRAILER SIGNAL CONVERTER,” filed on Mar. 1, 2013, which are all herebyincorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates generally to a signal converter and, moreparticularly, to an improved trailer signal converter for interfacingwith a towing vehicle

BACKGROUND OF THE INVENTION

Towed vehicles, such as trailers, have brake signals that operate basedon the braking signals of the towing vehicle. As is well known in theart, the braking signals of the towing vehicle are electricallyconnected to the braking system of the towed vehicle, such as via anelectrical adapter, or the like. Typically, the signaling system of thetowing vehicle has a signal lamp and a brake lamp that are operated byat least two separate filaments. However, most trailer signal systemsusually combine the turn and brake signals into a single lamp with asingle filament. Accordingly, an adapter or circuitry is often requiredin order to interface the signal system of the towing vehicle with thesignal system of the towed vehicle or trailer.

Older model towing vehicles, such as pickup trucks, typically use aswitch on the brake pedal to activate the brake lights. The switch isconfigured to send a signal, such as a 12 volt signal, to the vehicle'sbraking system or light controls. A towed vehicle may interface with thelight signals of the towing vehicle, either directly or through aconverter, to provide signals to the lights of the towed vehicle.

Trailer brake controllers are sometimes after-market devices that aredesigned to interface with the braking system of a towing vehicle andprovide braking signals and light signals to a towed vehicle. Suchtrailer brake controllers commonly include a manual control to apply thebrakes of the towed vehicle. When such action is taken, the lights ofthe towed vehicle must be activated. To activate the lights, trailerbrake controllers are often configured to apply a voltage to the signalwire of the brake pedal switch. As described above, this signalactivates the towing vehicle brake lights which in turn activates thetowed vehicle brake lights. The towed vehicle brake lights are commonlythe turn-signal lights activated together.

Newer model towing vehicles have replaced the brake pedal switch with apedal position sensor. The pedal position sensor does not use the same12 volt signal that was previously used with the pedal switch, butinstead uses a signal that lacks the low impedance and voltage to drivethe stop lamp input of the trailer brake controller. The sensor signalis then used as an input into a controller on the towing vehicle. Thisnew design poses a problem for brake controllers, in that they are nolonger able to receive the stop lamp signal when the towing vehiclebrakes are applied.

In addition, on older model vehicles, the 12 volt signal from the pedalwas able to be used to drive the brake lights on the towing vehicledirectly, and therefore was able to also drive the trailer lightsthrough a relay output. However, on newer model vehicles the pedalposition sensor does not provide an adequate output to drive the lightsand is not readily accessible. This new design poses a problem for brakecontrollers, in that they are no longer able to communicate theappropriate signal when the manual brake controls are applied.

Some towing vehicle manufacturers have provided an alternate accesspoint to the stop lamp input signal. However, this output may not havethe low impedance required to drive the stop lamp input of the brakecontroller. In addition, the alternate access point does not provide anymeans for the brake controller to drive the towing or towed vehiclebrake lights.

In certain jurisdictions, alternative wiring and lighting systems areused to signal trailer braking. For example, in some countries, thetrailer vehicle brake lights include both an amber light to indicate aturn signal and a red light to indicate a stop signal. Therefore, it isfurther required that a converter must be capable of outputting signalsto drive both the turn signal light and the stop signal light on eachside of the trailer.

Therefore, an improved solution is needed.

SUMMARY

A trailer signal converter is generally provided. The signal converterincludes a plurality of inputs, including a first towing vehicle turnlight signal, a second towing vehicle turn light signal, and a trailerbrake signal. The trailer signal converter further includes one or moreoutput signals to the trailer vehicle.

In an embodiment, the trailer signal converter is configured tointerface with a two-wire system on the trailer. The output signals mayinclude a first trailer vehicle turn light signal output and a secondtrailer vehicle turn light signal output. The trailer signal convertermay be configured to turn on both the first and second trailer vehicleturn lights when both the first and second towing vehicle turn lightsignals are on and the trailer brake signal is off, or when the trailerbrake signal is on and both the first and second towing vehicle turnlight signals are off. Further, the trailer signal converter may beconfigured to flash the first trailer vehicle turn light and turn on thesecond trailer vehicle turn light when the trailer brake signal is onand the first towing vehicle turn light signal is flashing and thesecond towing vehicle turn light signal is off.

In an embodiment, the trailer signal converter is configured tointerface with a three-wire system on the trailer. The output signalsmay include a first stop light output and a second stop light output.The first and second stop light outputs may turn on anytime the brakecontrol signal from the brake controller is on.

DESCRIPTION OF THE DRAWINGS

Operation of the invention may be better understood by reference to thefollowing detailed description taken in connection with the followingillustrations, wherein:

FIG. 1 illustrates a component diagram of a trailer brake and lightsignal system.

FIG. 2 illustrates a component diagram of a trailer brake and lightsignal system having a direct signal from the brake controller to thesignal converter.

FIG. 3 illustrates a circuit diagram of trailer signal converter with athree-wire output scheme.

The invention has been described above and, obviously, modifications andalterations will occur to others upon a reading and understanding ofthis specification. The claims as follows are intended to include allmodifications and alterations insofar as they come within the scope ofthe claims or the equivalent thereof.

DETAILED DESCRIPTION

While the invention is described herein with reference to severalembodiments, it should be clear that the invention should not be limitedonly to the embodiments disclosed or discussed. The description of theembodiments herein is illustrative of the invention and should not limitthe scope of the invention as described or claimed.

As shown in FIGS. 1 and 2, a system for controlling the brake and stoplights of a trailer vehicle is generally presented. The system mayinclude various components, as described below. The components may bestandard components on a towing vehicle, such as a truck or automobile,or after-market components configured to be integrated with thecomponents of a towing vehicle.

The system includes a brake controller 10 configured to operate thebrakes of a towed vehicle or trailer. The brake controller 10 may be anafter-market brake controller 10 installed on the towing vehicle, or maybe integrated with the braking system of a towing vehicle. Whetherintegrated or aftermarket, the brake controller 10 may provide a brakeoutput signal to the brakes of the towed vehicle or trailer.

In an embodiment, the brake output signal may be a pulse-width modulated(PWM) signal sent to the trailer brakes. The trailer brakes may beelectric brakes configured to be receive a PWM signal. The PWM signalmay vary in duty cycle depending on the braking power to be applied bythe trailer brakes. For example, a signal with an increased duty cyclemay provide increased braking power over a signal with a lesser dutycycle.

The brake controller 10 may be configured to receive a signal from abrake pedal 12 of the towing vehicle. Specifically, the brake controller10 may receive a signal from a pedal position switch 14 located near thebrake pedal. The pedal position switch 14 may output a signal when thepedal 12 is depressed to a preset distance. The signal may be a lowvoltage, low power signal.

The brake controller 10 may receive the input signal from the pedalposition switch 14 and output the PWM brake output signal to the trailerbrakes. The duty cycle of the PWM brake output signal may be based onany appropriate factors, such as acceleration, deceleration, speed,brake pedal position, or any other parameters.

The brake controller 10 may be connected to a brake control plug 16 onthe towing vehicle. The brake control plug 16 may interface with thetowing vehicle and include both inputs from the towing vehicle andoutputs from the brake controller 10. As shown, the brake control plug16 may provide a power input signal 18, such as a 12 volt signal, fromthe towing vehicle battery 20. The brake control plug 16 may alsoinclude a ground signal 22 and a brake output signal 24. The brakeoutput signal 24 may be a discreet signal, such as a 12 volt signal, ora PWM signal.

The brake controller 10 may include a manual trailer brake activation,such as a button or lever. Engaging the button or lever may activate thetrailer brakes without activating the towing vehicle brakes. When themanual brake button is pushed, the brake controller 10 may activate thebrake output signal 24. The signal 24 may then be sent to the trailer toengage the trailer brakes, independent of any braking signal applied tothe towing vehicle brakes.

The towing vehicle may include a braking signal connector, such as a7-pin connector 26. The 7-pin connector 26 may include a plurality ofwires to carry signals from the towing vehicle, including a rightturn/stop output 28 and a left turn/stop output 30 from the vehicle. Thetowing vehicle may drive the right and left turn/stop output signals 28,30 and therefore, these signals cannot be driven by the brake controller10. Because the brake controller 10 no longer has access to directlydrive the brake lamps on the towing or towed vehicle, an additionalcomponent may be required in order to initiate the trailer brake lightin response to the manual brake activation.

In an embodiment, the towing vehicle may provide a right turn/stop lightoutput 28 and a left turn/stop light output 30 to provide signals to atrailer with a 2-wire system with combined stop and turn lights. In anembodiment, the towing vehicle may provide a right turn light, left turnlight, and stop light outputs to provide signals to a trailer with a3-wire system having a separate stop and turn light on each tail light.For each configuration, the tail lights may require an additionalcomponent to initiate the appropriate lighting when the manual brakeactivation is applied.

In an embodiment, the system may include a signal converter 32. Thesignal converter 32 may be configured to receive inputs from both thevehicle and the brake controller 10 and drive the signal light outputsto the trailer. The signal converter 32 may be configured to receiveinputs from both the vehicle and the brake controller and drive theright and left turn/stop output signals to trailers with a two-wireconnection. Alternatively, the signal converter 32 may be configured todrive the separate turn and stop lights on a three-wire system. Forexample, the signal converter 32 may be configured to drive the stoplights while the right-turn and left-turn signals are passed through inthe three-wire configuration, as further described below.

As shown in FIG. 1, the right and left turn/stop signals 28, 30 may becut or spliced before they reach the 7-pin connector. The signal wires28, 30 may then be connected and used as inputs to the signal converter32. In an embodiment, the right and left turn/stop signals 28, 30 maypass through the converter instead of being cut or spliced.

In order to drive the trailer brake lights, the signal converter 32 mustalso receive a signal from the brake controller 10 indicating when themanual brake is activated. One solution is to run a wire from the brakecontroller 10, often located in the cab of the vehicle, to the signalconverter 32, often located near the rear of the vehicle. Alternatively,the signal converter 32 may utilize the brake signal output 24 of thebrake controller 10 as an input. For example, the signal converter mayaccess the brake signal output 24 at the 7-pin connector 26. In anembodiment, the brake output signal wire 24 may be spliced to provideboth a signal to the trailer brakes and an input to the signal converter32 in response to activation of the brake controller manual brake.

The signal converter 32 may be configured to read and decode the PWMsignal of the brake output signal 24. For example, the signal converter32 may be programmed with preset duty cycle thresholds or ranges todetermine when the PWM input signal is in a stop condition. In anembodiment, the signal converter 32 may be programmed to read a brakingcondition when the duty cycle of the brake output signal 24 is between7% and 97%. However, it will be appreciated that the trailer signalconverter 32 may apply any appropriate duty cycle threshold or range indetermining a braking condition.

With reference to the circuit diagram in FIG. 1, the signal converter 32may be configured to selectively output the right and left stop/turnoutput signals 34, 36, as required in a two-wire configuration. Whenonly the right stop/turn signal 28 or only the left stop/turn signal 30is on (such as flashing), and the manual brake is not activated, thesignal converter 32 may act as a pass-through for the left and rightstop/turn signals 28, 30 to turn on or flash the left and rightstop/turn output signals 34, 36. When both of the left and rightstop/turn signals 28, 30 are on, and the manual brake is not activated,the signal converter 32 may also act as a pass-through for the left andright stop/turn signals 28, 30.

When the manual brake is activated, the signal converter 32 receives asignal indicating that the manual brake is activated. The signalconverter 32 will turn on the right and left stop/turn signals 28, 30anytime the manual brake is activated unless one of the turn signals isengaged. If a turn signal is engaged, then the turn signal side willflash on both the vehicle and the trailer, while the opposite light willstay active only on the trailer.

When the brake control signal 24 is activated and both the right andleft towing vehicle turn signals 28, 30 are on, trailer signal converter32 may flash the left and right trailer vehicle turn lights.Alternatively, when the brake control signal 24 is activated and boththe right and left towing vehicle turn signals 28, 30 are on, trailersignal converter 32 may hold the left and right trailer vehicle turnlights on.

In an embodiment illustrated in FIG. 3, the signal converter 32 may beconfigured to interface with a three-wire system. For example, thesignal converter 32 may be configured to drive a separate stop lights 38in addition to the right and left turn signal lights 34, 36.

FIG. 3 illustrates a signal converter 32 having a plurality of inputsand a single output. The inputs may be received from the towing vehicleand output to the 7-pin connector 26 on the tow vehicle which connectsto the trailer. The wires on the input side of the signal converter 32may include the right and left tow vehicle turn signals 28, 30, thebrake signal 24 and stop light 25, as well as a tail light signal,reverse signal, and a ground signal. While FIG. 3 illustrates only twowires connected as inputs to the signal converter 32, it will beappreciated that the signal converter 32 may be configured to receiveany number of signals as inputs, or all the signals as inputs. Thesignal converter 32 may act as a pass through for any signals other thanthe inputs described below and may pass the signals onto the trailer.Further, the signal converter may act as a buffer for all the signals toprovide over-current, shorting, and over-temperature protection.

In the three-wire system, the signal converter 32 may act as a passthrough for the right vehicle turn signal 28 and left vehicle turnsignal 30. In other words, anytime the right tow vehicle turn signal 28is on the right trailer turn signal 34 will be on, and anytime the lefttow vehicle turn signal 30 is on the left trailer turn signal 36 will beon. The right and left stop light signals 38, 40 will turn on anytimethe brake signal 24 is on. Alternatively, as shown in FIG. 3, the rightand left tow vehicle turn signals 28, 30 may run directly through the7-pin connector 26 instead of inputs to the signal converter 32, asillustrated in FIG. 3.

The signal converter 32 may include two input signals, namely thetrailer brake signal 24, and a stop light signal 25. As described above,the trailer brake signal may come from the trailer brake controller 10and may be a PWM signal. The trailer signal converter 32 may apply athreshold or range to the PWM signal duty cycle to determine a brakingcondition, as explained above.

The stop light signal 25 may be tied to the towing vehicle brake lightsignal. The stop light signal 25 may turn on anytime the towing vehiclebrakes are applied.

The signal converter 32 may drive the stop light signal 38 based thetrailer brake signal 24 and tail light signal 25. When either thetrailer brake signal 24 or stop light signal 25 are on, the signalconverter may turn the stop light signal 38 on. Further, when both thetrailer brake signal 24 and stop light signal 25 are on, the signalconverter may turn the stop light signal 38 on.

The invention has been described above and modifications and alterationswill occur to others upon a reading and understanding of thisspecification. The claims as follows are intended to include allmodifications and alterations insofar as they come within the scope ofthe claims or the equivalent thereof.

Having thus described the invention, we claim:
 1. A trailer signalconverter comprising: first and second towing vehicle turn lightsignals; a trailer brake signal; and first and second trailer vehicleturn light signal outputs, wherein the first and second trailer vehicleturn lights are on when both the first and second towing vehicle turnlight signals are on and the trailer brake signal is off, or when thetrailer brake signal is on and both the first and second towing vehicleturn light signals are off.
 2. The trailer signal converter of claim 1,wherein the first trailer vehicle turn light flashes and the secondtrailer vehicle turn light is on when the trailer brake signal is on andthe first towing vehicle turn light signal is flashing and the secondtowing vehicle turn light signal is off.
 3. The trailer signal converterof claim 2, wherein the first towing vehicle turn light signal is theleft towing vehicle turn light signal and the first trailer vehicle turnlight signal is the left trailer vehicle turn light signal.
 4. Thetrailer signal converter of claim 2, wherein the second towing vehicleturn light signal is the right towing vehicle turn light signal and thesecond trailer vehicle turn light signal is the right trailer vehicleturn light signal.
 5. The trailer signal converter of claim 1, whereinthe trailer brake signal is an output signal from a trailer brakecontroller.
 6. The trailer signal converter of claim 1, wherein a brakeoutput signal is generated in response to activation of a manualcontrol.
 7. The trailer signal converter of claim 1, wherein an outputsignal from a trailer brake controller is a pulse-width-modulated (PWM)signal.
 8. The trailer signal converter of claim 1, wherein the PWMsignal is decoded.
 9. The trailer signal converter of claim 8, whereinwhen the PWM signal duty cycle is between 7% and 97% a braking conditionis determined.
 10. The trailer signal converter of claim 1, wherein thefirst trailer vehicle turn light is on when the first towing vehicleturn light signal is on and the second towing vehicle turn light signaland trailer brake signal are both off.
 11. The trailer signal converterof claim 1, wherein the first and second trailer vehicle turn lightsflash when the first and second towing vehicle turn light signals areflashing and the trailer brake signal is on or off.
 12. The trailersignal converter of claim 1, wherein the first and second trailervehicle turn lights are on when the first and second towing vehicle turnlight signals are flashing and the trailer brake signal is on.
 13. Atrailer signal converter comprising: a trailer brake signal input and abrake light signal input; and a stop light output signal, wherein thestop light output signal is on when the trailer brake signal input orthe brake light signal input is on, or when both the trailer brakesignal input and the brake light signal input are on.
 14. The trailersignal converter of claim 13, wherein the trailer brake signal input isa pulse-width-modulated (PWM) signal.
 15. The trailer signal converterof claim 13, wherein the PWM signal is decoded.
 16. The trailer signalconverter of claim 14, wherein a braking condition is determined whenthe PWM signal duty cycle is between 7% and 97%.
 17. The trailer signalconverter of claim 13, wherein the trailer brake signal input is anoutput from a trailer brake controller.
 18. The trailer signal converterof claim 13, wherein the trailer brake signal input is generated inresponse to activation of a manual brake control.
 19. A trailer signalconverter comprising: first and second towing vehicle turn lightsignals; a pulse width modulated trailer brake signal; and first andsecond trailer vehicle turn light signal outputs, wherein the firsttrailer vehicle turn light flashes and the second trailer vehicle turnlight turn on when the trailer brake signal is on and the first towingvehicle turn light signal is flashing and the second towing vehicle turnlight signal is off.
 20. The trailer signal converter of claim 19,wherein the first and second trailer vehicle turn lights are on whenboth the first and second towing vehicle turn light signals are on andthe trailer brake signal is off, or when the trailer brake signal is onand both the first and second towing vehicle turn light signals are off.